A Briggs-Rauscher Reaction-based Spectrometric Assay to Determine Antioxidant Content in Complex Matrices in Low Technology Environments

Authors

  • Ankit Singhal International School Basel, Fleischbachstrasse 2, CH-4153 Reinach, Switzerland;, Email: ankit.singhal@isbasel.ch
  • Philipp Grögli Synthetic Molecules Technical Development, F. Hoffmann - La Roche Ltd, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
  • Bernd Geiser Synthetic Molecules Technical Development, F. Hoffmann - La Roche Ltd, Grenzacherstrasse 124, CH-4070 Basel, Switzerland
  • Alina Handl Synthetic Molecules Technical Development, F. Hoffmann - La Roche Ltd, Grenzacherstrasse 124, CH-4070 Basel, Switzerland

DOI:

https://doi.org/10.2533/chimia.2021.74

PMID:

33637152

Keywords:

Antioxidant, Ascorbic acid, Briggs-rauscher, Spectrometric assay

Abstract

The Briggs-Rauscher (BR) reaction is free radical based where the kinetics of formation of different iodide species leads to potentiometric and color oscillations. These oscillations were monitored in this study using a UV/Vis attenuated total reflection probe to develop an assay to measure the antioxidant content in complex matrices. The periodicity of the BR reaction was found to be very consistent (range 24–25 seconds, n = 16). Adding various amounts of ascorbic acid, a well-known antioxidant, led to an inhibition of the reaction with a linear calibration curve of antioxidant periodicity time (APT, r 2 > 0.99). The validity of this test in complex matrices was studied by determining the APT of nine fruits, and the resulting antioxidant capacity in ascorbic acid equivalency was calculated. The results generated by this assay were found be accurate through comparison with the well-established FRAP assay. These results show that visual or spectrometric monitoring of BR reaction can be used as a reliable, quick, and inexpensive alternative to more established assays with the added advantage that values generated from this assay is at pH 2 which is similar to that in the human stomach.

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Published

2021-02-28

How to Cite

[1]
A. Singhal, P. Grögli, B. Geiser, A. Handl, Chimia 2021, 75, 74, DOI: 10.2533/chimia.2021.74.